Hui-Yu Tsai a, Yi-Shuan Hwang b, Ho-Ling Liu a. a Department of Medical. Imaging and Radiological Science, Chang Gung University, Taoyuan,. Taiwan ...
Abstracts / Physica Medica 30 (2014) e75ee121
e89
IMPACT OF AUTOMATIC TUBE CURRENT MODULATION ON CT DOSE AND IMAGE QUALITY FROM A VIEW OF NATIONWIDE SURVEY
MEASUREMENT OF EXTRA LOW FREQUENCY ELF ELECTROMAGNETIC FIELDS IN INDOOR WORKING AREAS
Hui-Yu Tsai a, Yi-Shuan Hwang b, Ho-Ling Liu a. a Department of Medical Imaging and Radiological Science, Chang Gung University, Taoyuan, Taiwan; b Department of Diagnostic Radiology and Intervention, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
A. Skouroliakou a, P. Kontaxis a, S. Anagnostakis a, S. Triantopoulos a, S. Tsantis b. a Department of Energy Technology Engineering, Technological Educational Institute of Athens; b Department of Medical Physics, School of Medicine, University of Patras
Background: This study aims to survey and investigate the impact of using the current use of automatic tube current modulation (ATCM) in clinical applications on image quality and radiation dose. Materials and methods: CT scanners which used clinical adult abdominal scanning protocols were surveyed nationwide. If ATCM was clinically used, the mAs of an average-weight patient's mid-liver image was recorded to calculate the appropriate volumetric computed tomography dose index (CTDIvol). If ATCM was not applied, CTDIvol were recorded directly. The CTDIvol for abdominal scanning represented the average clinical adult abdominal dose in Taiwan. Additionally, a custom ATCM phantom was designed to survey the radiation dose and image quality for CT scanners using ATCM. After CT scanning, the recorded CTDIvol and dose-length product (DLP) values, and investigated image quality, were compared for turning-on and turning-off ATCM in the same CT scanner. Results: Analyses of survey data showed a significant dose decrease for diagnostic CT scanners between with using ATCM (12±4 mGy) and without using ATCM (15±5 mGy). Evaluations of the custom phantom showed no significant difference of CTDIvol, DLP, noise between turning-on and turning-off ATCM. Discussion: The use of ATCM effectively reduces dose for diagnostic CT scanners from a nationwide view. The custom ATCM phantom was suitable for testing ATCM functions.
Background: Extra low frequency (ELF) electromagnetic fields are emitted by electrical appliances and domestic electrical wiring installations located in indoor areas. The need for updated measurements and estimations of ELF-fields levels has been accepted by all National organizations, towards compliance with international standards and acquirement of dosimetric data for epidemiological studies. Since numerous individuals spend 8 hours per day in their office, measurement and evaluation of ELF-fields levels within working environment is considered of importance. Material & Methods: The presented study involves the measurement of ELF-field strength in 50 working areas (i.e. offices of administrative staff in which more than 80% of its working hour is spent). The electric equipment located in the aforementioned areas was recorded along with several characteristics concerning category, type and operational average time in daily basis. All measurements were performed with NARDA EFA 300 spectral field meter which is appropriate for frequency range between 0-100kHz. ELF rms and max values of magnetic field strength were obtained from maximum spots, specific distances from the equipment and employee locations during working hours, with electrical equipment in both stand by and functioning modes. Each measurement’s duration was 6 minutes and it was repeated twice. Results: Magnetic field strength was dominated from 50Hz fields (Greek frequency of the electric supply system). Peak values were measured close to photocopy electric equipment while it was functioning, with magnetic field strength values up to 0,8mΤ when it was actually operating. On the other hand, magnetic field strength dropped with when the distance from the equipment was increased. High values of magnetic field strength were also measured close to the electrical sub panels but in most cases these were installed in low occupancy areas. ELF fields from pc central processing units and monitors were in most cases less than 0,1mT at operating position. Discussion: Results are generally in accordance with corresponding measurements performed by other groups. In cases where the values are high simple reduction methods should be suggested. As maximum and rms values had considerable differences, it might be advisable to consider both at dosimetric extrapolations and electric appliance’s standards.
Figure 1A. custom ATCM phantom was designed and shown as the parts of pelvis (a), abdomen (b), chest (c), and combined together (d).
MEASUREMENT OF IODINE (I125) RADIOACTIVE SOLID WASTE DERIVED FROM RADIO IMMUNE ANALYSIS (RIA-IRMA) PERFORMED ANNUALLY IN ”THEAGENIO” NUCLEAR MEDICINE DEPARTMENT Kotzassarlidou Maria a, Mone Ioanna b, Giannopulou Katerina a, Kirilidou Pipintakou Ageliki a, Chatzimarkou Michali a, Sidiradi Olga a, Aikaterini a. a ”THEAGENEIO” Cancer Hospital, Thessaloniki, Greece; b Aristotelio University of Thessaloniki, Greece
Figure 2. Noise distribution for chest (a), abdomen (b) , and pelvis as ATCM was turn on.
Figure 3. Noise distribution for chest (a), abdomen (b) , and pelvis as ATCM was turn off.
Introduction: I-125 is the preferred radioisotope for tagging antibodies in radioimmunoassay procedures(RIA-IRMA), resulting in significant volume of contaminated solid waste, mainly tubes and absorbent paper. I-125 solid waste management is nuclear medicine physicists’ corcern, which must be in accordance with Geek Legislation. Objective: This study aims to present real practice data of I-125 activityconcentation in solid waste derived from radioimmunoassay testsperformedin the Nuclear Medicine Department of ”THEAGENEIO” Cancer Hospital throughout one year.Brief description of management program for the above mentioned waste, applied in our department is given. Materials and methods: Calibration factor(CF), converting true count rate to I-125 activity was defined, using a standard source, I-129(equivalent to
